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研究生： 席馬地
Roland Martin
論文名稱： 含粉土層之砂土層中使用碎石樁以防止液化的數值分析研究
A NUMERICAL INVESTIGATION ON STONE COLUMNS AS A COUNTERMEASURE FOR LIQUEFACTION OF SANDY SOIL STRATUM WITH INTRALAYERS OF SILT
指導教授： 陳慧慈
HUEI-TSYR CHEN
口試委員:
學位類別： 碩士
Master
系所名稱： 工學院 - 土木工程學系
Department of Civil Engineering
畢業學年度： 99
語文別： 英文
論文頁數： 98
中文關鍵詞： 液化 、粉土層 、數值模擬 、碎石樁
外文關鍵詞： liquefaction, intralayers of silt, stone column, numerical simulation
相關次數： 點閱：13  下載：0 
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    • 強震往往會造成基礎和結構物的破壞以及人員的傷亡。從大地地震工程的觀點，在強烈地震侵襲下，一個經常會發生的現象就是土壤液化。大家一致同意的觀點是液化容易發生於均勻的鬆砂土層。實際上，砂土層有可能含有粉土層；在這具有更小的滲透係數的粉土層底面，在大震時會產生具有高孔隙水壓的水膜，需要長時間才能消散完畢，是許多在地震動停止一段時間後才發生破壞的原因。
    本研究利用三維非線性有效應力有限元素法分析土層的受震反應。首先以離心機試驗的結果進行驗證，然後再以九個數值分析模式進行參數分析，以瞭解含粉土層之砂土層的液化行為與在該土層內使用碎石樁以防止液化的機制。
    使用碎石樁可以延緩及降低超額孔隙水壓的上升，但是在某些情況下，還是無法避免液化的產生。一般而言，碎石樁的使用可以提高土層的勁度，因而降低了地表沉陷，其值隨碎石樁面積的增加而增加。對於含粉土層之砂土層而言，粉土層的存在會降低液化區的範圍以及地表沉陷，但是在粉土層的底部會產生具有高孔隙水壓的水膜，且須要長時間才能消散完畢。隨著粉土層越多，使用碎石樁的有效性會降低。

    Strong earthquakes can cause serious damage to the failure of foundations and structures, which may result in loss of lives. From the geotechnical point of view, for a large earthquake one of the frequently occurred phenomenon is known as liquefaction. The common consensus about this phenomenon is that liquefaction may easily occur in a uniform loose sandy soil stratum. In reality, the presence of intralayers of silt may be found in the field. The smaller permeability of these silt layers may develop a water film at its bottom with a high pore water pressure, leading to failure of ground even long after the earthquake shaking stopped.
    In this study, the seismic responses of sandy soil stratum with silt layers were obtained by using nonlinear 3D effective stress finite element program. Verification and validation of the program was done first by comparing with centrifuge test results which are in good agreement. The parametric studies using nine numerical models were then conducted to investigate the behavior of liquefiable sand-silt stratum under strong earthquakes and to gain a better understanding of the mechanism of stone columns as a countermeasure in a liquefiable sand-silt stratum.
    The use of stone columns can delay and reduce the accumulation of excessive pore water pressure; although in some cases liquefaction cannot be avoided. The stiffening benefit from stone columns also reduces the ground settlement which is in parallel with the area of treatment; but the effectiveness of stone columns decreases as the more intralayers of silt are introduced to the stratum. The presence of intralayers of silt will reduce the extent of liquefaction and significantly reduce the ground settlement; however, the large pore water pressure beneath each silt layer forms the water film which requires longer time to dissipate.

    摘 要 i ABSTRACT ii ACKNOWLEDEMENTS iii LIST OF CONTENTS iv LIST OF TABLES vii LIST OF FIGURES viii NOTATIONS xi CHAPTER 1. INTRODUCTION 1 1.1. Background 1 1.2. Research Objectives 1 1.3. Organization of Thesis 2 CHAPTER 2. LITERATURE REVIEW 3 2.1. Introduction 3 2.2. Liquefaction 3 2.2.1. Definition of Liquefaction 3 2.2.2. Earthquake Liquefaction 4 2.2.3. Susceptibility of Liquefaction 4 2.3. Sand with Intralayers of Silt 5 2.3.1. Characteristic of Silt 5 2.3.2. Liquefaction of Sand with Intralayers of Silt 6 2.4. Countermeasure of Liquefaction 8 2.4.1. Type of Soil Countermeasure 8 2.4.2. Stone Column 9 CHAPTER 3. NUMERICAL FORMULATION 11 3.1. Basic Equation of Motion for Porous Media 11 3.2. Description of Cap Model and Pore Pressure Model 13 3.3. Numerical Integration 17 CHAPTER 4. VERIFICATION AND VALIDATION 18 4.1. Introduction 18 4.2. Description of Centrifuge Test 18 4.3. Description of Numerical Model 19 4.4. Input Motion of Numerical Simulation 19 4.5. Discussion of Numerical Simulation Result under Harmonic Input Motion 20 4.5.1. Settlement Analysis 20 4.5.2. Pore Water Pressure Analysis 20 CHAPTER 5. NUMERICAL RESULTS AND DISCUSSIONS 22 5.1. Introduction 22 5.2. Model Description 22 5.3. Earthquake Input Motion 23 5.4. Comparison of Results from Sand, Silt 1, and Silt 2 Models 24 5.4.1. Excessive Pore Water Pressure 24 5.4.1.1. Chiayi Input Motion 24 5.4.1.2. Taipei Input Motion 25 5.4.2. Settlement 25 5.4.2.1. Chiayi Input Motion 25 5.4.2.2. Taipei Input Motion 26 5.4.3. Summary 26 5.5. Excessive Pore Water Pressure of Liquefiable Ground Using Stone Columns as Countermeasure for Liquefaction 26 5.5.1. Chiayi Input Motion 26 5.5.1.1. Sand Model 26 5.5.1.2. Silt 1 Model 27 5.5.1.3. Silt 2 Model 27 5.5.2. Taipei Input Motion 28 5.5.2.1. Sand Model 28 5.5.2.2. Silt 1 Model 28 5.5.2.3. Silt 2 Model 29 5.5.3. Summary 29 5.6. Settlement of Liquefiable Ground Using Stone Columns as Countermeasure for Liquefaction 29 5.6.1. Chiayi Input Motion 29 5.6.1.1. Sand Model 29 5.6.1.2. Silt 1 Stratum 30 5.6.1.3. Silt 2 Model 30 5.6.2. Taipei Input Motion 31 5.6.2.1. Sand Model 31 5.6.2.2. Silt 1 Stratum 31 5.6.2.3. Silt 2 Stratum 31 5.6.3. Summary 31 CHAPTER 6. CONCLUSIONS AND RECOMMENDATIONS 33 6.1. Conclusions 33 6.2. Recommendations 33 REFERENCES 34

    1. Kokusho T. (1999), “Water Film in Liquefied Sand and Its Effect on Lateral Spread”, Journal of Geotechnical and Geoenvironmental Engineering, ASCE, Vol. 125, No.10, pp 817-826
    2. Poulos S.J., Castro G., France J.W. (1985), “Liquefaction Evaluation Procedure”, Journal of Geotechnical and Geoenvironmental Engineering, ASCE, Vol. 111, No.6, pp 772-793
    3. Karbasi M.S., Byrne P.M. (2007), “Seismic Liquefaction, Lateral Spreading, and Flow Slides: a Numerical Investigation into Void Redistribution”, Canadian Geotechnical Journal, Vol. 44, No. 7, pp. 873-890
    4. Lee C.J., Wei Y.C., Lien H.C., Chen H.T. (2011), “Centrifuge Modeling on the Seismic Responses of Sandy Deposit with a Thin Silt Seam”, 8th International Conference on Urban Earthquake Engineering, Tokyo Institute of Technology, Tokyo, Japan
    5. Olson S.M., Stark T.D. (2002), “Liquefied Strength Ratio from Liquefaction Flow Failure Case Histories”, Canadian Geotechnical Journal, Vol. 39, pp. 629-647
    6. Dikmen S.U., Tonaroglu M. (2008), “Liquefaction Analysis of Saturated Sand Deposits with Silt Layers Subjected to 1 and 2 Components of Earthquake Motion”, The 14th World Conference on Earthquake Engineering, Beijing, China
    7. Mavituna O., Teymur B. (2008), “Effect of Improving Soil As a Countermeasure for Liquefaction”, The 14th World Conference on Earthquake Engineering, Beijing, China
    8. Kokusho T., Kojima T. (2002), “Mechanism for Post-Liquefaction Water Film Generation in Layered Sand”, Journal of Geotechnical and Geoenvironmental Engineering, ASCE, Vol.128, No.2, pp. 129-137
    9. Jou, J.J. (2000), “Seismic Responses Analysis of Pile Foundations of Bridges”, PhD. Thesis, Department of Civil Engineering, National Central University, Chungli, Taiwan (in Chinese)
    10. Wijaya M.N., Chen H.T. (2010), “ Seismic Response of Bridge Pile Foundation in a liquefiable Soil Stratum Underlain by Irregular Bedrock”, Master Thesis, Department of Civil Engineering, National Central University, Chungli, Taiwan
    11. Adalier K., Elgamal A-W., Meneses J., Baez J.I. (2003), “Stone Columns as Liquefaction Countermeasure in Non-Plastic Silty Soils”, Soil Dynamics and Earthquake Engineering, Vol. 23, No. 7, pp. 571-584
    12. Adalier K., Elgamal A-W. (2002), “Seismic Response of Adjacent Dense and Loose Saturated Sand Columns”, Soil Dynamics and Earthquake Engineering, Vol. 22, No.2, pp. 115-127
    13. Lu J., Elgamal A-W., Yang Z., Adalier K. (2004), “Numerical Analysis of Stone Column Reinforced Silty Soil”, Proceedings of The 15th Southeast Asian Geotechnical Conference (15SEAGC), Vol. 1, Bangkok, Thailand, pp. 23-26
    14. Shentan T. (2006), “Soil Densification Using Vibro-Stone Columns Supplemented with Wick Drains”, 100th Anniversary Earthquake Conference, Moscone Convention Center, San Fransisco, USA
    15. Fiegel G.L., Kutter B.L., (1994), “Liquefaction Mechanism for Layered Soil”, Journal of Geotechnical Engineering, Vol. 120, No. 4, pp. 737-755
    16. Hazen A. (1920), Transactions of the American Society of Civil Engineers, Vol. 83, pp. 1717-1745
    17. Chen H.T., Chen W.H. (2005), “Effectiveness of Diaphragm Wall in Reducing The Potential of Soil Liquefaction Induced by Earthquake”, Second International Conference on Urban Earthquake Engineering, Tokyo Institute of Technology, Tokyo, Japan
    18. Kumar S.R. (2010), “Liquefaction of Sand and Its Countermeasure”, New Building Material and Construction World, NBM Media, October 2010
    19. Nesgaard E., Byrne P.M. (2005), “Flow Liquefaction due to Mixing of Layered Deposits”,
    20. Liu L., Dobry R. (1997), “Seismic Response of Shallow Foundation on Liquefable Sand”, Proc. Geotechnical Earthquake Engineering Satellite Conf., Japanese Geotechncial Society, pp. 103-108
    21. Andrianopoulos K., Bouckovalas G., Karamitros D., Papadimitriou A. (2006), "Effective Stress Analysis for The Seismic Response of Shallow Foundations on Liquefiable Sand", 6th European Conference on Numerical Methods in Geotechnical Engineering, Graz, pp. 211-216.
    22. Elgamal A-W., Zeghal M., Taboada V., Dobry R. (1996), “Analysis of Site Liquefaction and Lateral Spreading using Centrifuge Testing Records”, Soils and Foundations, Japanese Geotechnical Technology, Vol. 36, No. 2, pp 111-121
    23. Arulanandan K., Scott R.F. (1993), “Verification of Numerical Procedures for The Analysis of Soil Liquefaction Problems”, Proceedings of The International Conference on The Verification of Numerical Procedures for The Analysis of Soil Liquefaction Problems, Davis, California, USA
    24. Prakash S., Guo T. (1999), “Liquefaction of Silts and Silt-Clay Mixtures”, Journal of Geotechnical and Geoenvironmental Engineering, ASCE, Vol. 125, No. 8, pp 706-711
    25. Popescu R., Prevost J.H. (1993), ” Centrifuge Validation of a Numerical Model for Dynamic Soil Liquefaction”, Soil Dynamics and Earthquake Engineering, Vol. 12, pp. 73-90
    26. Kramer, Steven L. (1996), Geotechnical Earthquake Engineering, Prentice-Hall Inc., Englewood Cliffs, N.J., 653
    27. Chen W.F., Baladi G.Y. (1985), “Soil Plasticity and Implementation”, Elsevier Science publishing Co. Newyork.
    28. Pacheco M.P., Altschaeffl A.G., Chameau J.L. (1989), “Pore Pressure Prediction in Finite Element Analysis”, International Journal for Numerical Methods in Engineering; 13:477-491.
    29. Malvick E.J., Kutter B.L., Boulanger R.W. (2008), “Postshaking Shear Strain Localization in a Centrifuge Model of a Saturated Sand Slope”, Journal of Geotechnical and Geoenvironmental Engineering, ASCE, Vol. 134, No. 2, pp 164-174
    30. http://www.google.com/imgres?q=silt
    31. http://www.google.com/imgres q=stone+column+installation

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